Even where mastery=crit it was close enough and varied enough between fights for me to favour crit, under no circumstances did I find mastery > crit, about half of fight types I sim'd had crit > mastery though. Crit also means more healing from lvl90 talents, not something to be ignored.

Take from that what you will. I strongly suggest running your own sims to get the data you need

Take from that what you will. I strongly suggest running your own sims to get the data you need

This.

When simming myself somewhat thoroughly (I run batches of about 10-15 million sims when looking into this stuff for myself), I've actually only found 18,215 to be superior with HeavyMovement and HecticAddCleave. It varies depending on your gear, set bonuses and trinkets. In addition to that, the difference is pretty minimal anyway.